1. Field of the Invention
The present invention relates generally to integrated circuits, and more particularly but not exclusively to integrated circuit fabrication processes and structures.
2. Description of the Background Art
In the manufacture of integrated circuits, selective deposition refers to a process of depositing materials on selected surfaces of structures. Selective deposition does not require a mask, and thus obviates the need for associated lithography, etching, and resist removal steps. In selective chemical vapor deposition (CVD), selectivity is due to the different chemical behavior of reactants to different surfaces. For example, tungsten may be selectively deposited on a bare silicon substrate without the tungsten growing on a dielectric material. Due to nucleation matters, the tungsten starts to grow immediately on the silicon substrate while the nucleation on the dielectric material is retarded. Selective CVD processes are advantageous because they allow for self-alignment with respect to various structures, thus allowing for relatively tight design rules. Therefore, techniques for minimizing selectively loss in selective deposition processes are highly desirable.